Device and capsule for preparing a drink

ABSTRACT

The invention relates to a capsule associated with the perforating device of a machine used to prepare drinks by injecting water into the capsule. The capsule includes a side wall and a base forming a self-supporting shell, an upper wall enclosing a sealed volume inside the shell that contains a substance to be extracted, and a filter membrane in the sealed volume disposed on the base. The base has a peripheral portion and a central portion, the central portion extending beneath the peripheral portion with a depth and having a low wall portion configured to be perforated or cut by the perforating device in order to create one or more outlets for the drink flowing through the filter membrane. The peripheral portion comprises flow channels extending radially from the low wall portion to the side wall and being disposed between the support spokes to support the filter membrane.

The present invention relates to a capsule and a perforating device for preparing beverages, particularly “filter” type coffee.

Certain capsule systems are suitable for preparing “espresso” type coffee; these coffees generally require a high pressure of 2 to 8 bars. For “filter” type coffee (also known as “brewed coffee”) preparation systems, the water injection pressure must not be too high so as not to cause foaming, and the coffee grounds must be well wetted for good extraction. In existing systems, in order to ensure good extraction of the coffee contained in the capsule, the capsules are very large and are only partly filled with coffee, sometimes to less than 50% of the container volume. The problem is to ensure good extraction with low pressure because, when the capsule is very full, preferred channels form and part of the coffee is not wetted. Conventional capsules for filter coffee are very bulky, which causes problems in storing and transporting them, but also for the dimensions of the machine for extracting the coffee. There is also a need to reduce the quantity of materials used in packaging for environmental reasons.

An object of the invention is to provide a capsule and a device for preparing a hot drink by injecting hot water into the capsule which is compact and economical and which allow high degree of extraction at low pressure.

It is advantageous to provide a capsule and a device for preparing a hot drink which uses little packaging material.

It is advantageous to provide a capsule and a device for preparing a hot drink which can operate at low pressure for preparing filter coffee, while still having a high degree of extraction and with a compact and well-filled capsule.

It is advantageous to provide a capsule and a device for preparing a hot drink which is reliable and which makes it possible to obtain consistent and reproducible extraction from one capsule to the next.

It is advantageous to provide a capsule for preparing a hot drink that uses materials with a low environmental impact and in small quantities.

Objects of the invention are attained by the capsule according to claim 1, the capsule being associated with a perforating device of a machine for preparing a drink by injecting water into the capsule.

In the present application, a capsule is described which includes a side wall and a bottom wall forming a self-supporting shell, an upper wall enclosing a volume sealed within the shell containing a substance to be extracted, and a filter membrane within the sealed volume placed on the bottom wall. The bottom wall includes a peripheral portion and a central portion, the central portion extending below the filter membrane having a non-zero depth H3 and including a lower wall portion configured to be perforated or sectioned by a perforating device in order to create one or more escape passages for the outflow of the beverage passing through the filter membrane. The peripheral portion includes flow channels extending essentially radially from the lower wall portion toward the side wall, interposed between supporting rays extending to the level of the filter membrane and constituting supports for the filter membrane against the pressure of the water injected into the capsule and pressing on the substance contained in the capsule. In the present application is also described a perforating device, associated with the capsule, of a machine for preparing a drink by injecting water into the capsule.

The support rays and the flow channels form a corrugated surface, the generating lines of the corrugations extending essentially radially from the central portion to the side wall. Radially inward ends of the support rays surround a low chamber allowing the lower wall portion to be perforated and the perforating device to penetrate into the capsule without perforating the filter membrane.

The perforating device includes a perforating member for opening the bottom of the capsule, the perforating member including in one advantageous embodiment a blade having a circular, or essentially circular, shape configured so as to cut an opening in the lower wall portion of the bottom wall. The blade can advantageously comprise perforation points in the form of saw teeth.

The perforating member can be mounted on the free end of a tubular support having a central outflow passage.

In an embodiment, the blade includes an interruption such that the blade does not cover the full circle, the blade being configured so that the sectioned portion of the lower wall is not completely detached from the rest of the bottom wall.

According to an advantageous embodiment, the perforating device includes a plunger positioned in the central passage, the plunger being movable axially in a direction perpendicular to the filter membrane configured to rest against the filter membrane after perforation of the bottom wall of the capsule.

The plunger can include a grille for passage of the liquid through the plunger.

The perforating device can advantageously comprise a base having a corrugated surface with rays configured for good seating and positioning of the bottom wall of the capsule.

Other goals and advantageous aspects of the invention will appear from the claims or from the detailed description of an embodiment hereafter with reference to the appended figures, whereby:

FIG. 1 a is a perspective and sectional view of a capsule, without the upper wall, and of a perforating part of a device for preparing a drink, in a pre-perforation position, according to an embodiment of the invention;

FIG. 1 b is an enlarged view of the bottom part of the capsule and of the device according to FIG. 1 a;

FIG. 2 a is a figure similar to FIG. 1 a, with the perforating part in a position wherein the bottom of the capsule has been perforated;

FIG. 2 b is a perspective and partial section view of a portion of the bottom wall of the capsule and of the perforating part of the device in a perforation position;

FIG. 3 a is a section view of a capsule, without an upper wall, according to an embodiment of the invention;

FIGS. 3 b and 3 c are perspective views of the capsule of FIG. 3 a, seen from above and from below, without an upper wall and without any substance to be extracted inside the capsule, the filter inside at the bottom of the capsule being removed in FIG. 3 b to illustrate the bottom wall of the capsule;

FIGS. 4 a and 4 b are perspective views, respectively sectional, of the perforating portion of the device for preparing a drink according to an embodiment of the invention;

FIGS. 5 a and 5 b are perspective and section views, respectively, of a bottom wall of a device for preparing a drink from a capsule according to an embodiment of the invention; and

FIG. 6 is a perspective view of a central part of the perforating part of the device according to an embodiment of the invention.

Referring to the figures, a capsule 2 includes an internal volume 3 containing a substance to be extracted (not shown) hermetically sealed into the internal volume. A machine for preparing a drink, particularly a hot drink, associated with the capsule, includes a dedicated capsule carrier, one perforating part 4 whereof is illustrated in FIGS. 1 through 2 b. The perforating part 4 includes a base 8 and a perforating device 6.

The capsule 2 includes a bottom wall 16, a side wall 18 and an upper wall (not shown), glued or welded to the upper surface 20 of a rim 21 extending radially from the side wall to the opposite side of the bottom wall 16. The side wall 18 can have a slightly conical shape. The bottom wall and the side wall, as well as the rim, are preferably formed in a single piece, forming a rigid self-supporting shell. The upper wall is preferably in the form of a flexible membrane made of a polymer material, for example of a laminated plastic multilayer, the wall being welded to the rim 21, for example by heat sealing or by ultrasonic welding. The bottom, side and upper walls allow the substance for preparing a drink, particularly coffee grounds, to be enclosed inside the internal volume 3, thus making it possible to retain the freshness of the substance for a long period. Instead of coffee grounds, the substance to be extracted can also be tea leaves, powdered milk, powdered chocolate, freeze-dried broth, or other substances. The capsule and device according to the invention, however, has a configuration that is particularly advantageous for preparing a filter type coffee at low pressure and with little foaming.

The shell consisting of the side wall, the bottom wall and the rim can be made of injection-molded plastic or of a vacuum-formed multilayer sheet of plastic. The shell can be made entirely of plastic including polypropylene for example, but the invention also advantageously allows the shell to be formed of a material other than plastic or of a combination of materials such as laminates including plastic. In particular, other materials which can be used for forming the shell within the scope of this invention are cellulosic materials, that is materials consisting of fibers similar to the fibers used in the production of paper or cardboard. The cellulosic material can confer a certain rigidity and could be provided with a plastic or food-grade wax layer on the inner surface of the container to guarantee liquid retention and to reduce the diffusion of molecules through the wall. The capsule can also have an EVOH layer allowing substitution for aluminum; it reduces diffusion of molecules (oxygen) through the polypropylene multilayer.

The capsule also includes a filter membrane 22 positioned in the internal volume 3 of the capsule at the bottom of the capsule, separating the solid substances contained in the internal volume 3 from the escape channel for liquid outflow. The filter membrane 22 can advantageously be placed against the inner surface of the bottom wall 16 and, in one preferred embodiment, extending over the entire inner surface defined by the periphery of the bottom wall connecting to the side wall 18. The filter membrane 22 can preferably be partly glued where it is in contact with the surface of the bottom wall of the capsule, for example at its periphery or on the lines of the rays, in order to avoid collapse of the filter membrane when a certain pressure is applied by the water injected into the capsule. The filter membrane can be made of cellulosic material with a porosity that allows retention of solid matter but allows passage of liquids constituting the drink to be prepared at low pressure, particularly less than 2 bars or even less than 1.5 bars. This makes it possible in particular to prepare a filter type coffee requiring a long wetting time for the coffee grounds and slow extraction of the coffee compared to the preparation of “espresso” type coffee. Excessive foaming, not desired in filter coffee, is thus avoided.

The bottom wall 16 includes a central portion 24 and peripheral portion 23, the central portion running below the peripheral portion 23 at a depth H3. The central portion includes a lower wall portion 25 configured to be perforated or sectioned by the perforating device 6 so as to create one or more escape passages for the outflow of the drink passing through the filter membrane. The peripheral portion 23 includes flow channels 26 extending radially from the low central portion toward the side wall, interposed between the support rays 28 extending to the level of the filter membrane and constituting supports for the filter membrane against pressure from the water injected into the capsule and pressing on the substance contained in the capsule in order to force passage of the liquid to be extracted through the filter. The support rays 28 and the flow channels 26 thus constitute a corrugated surface, the generating lines of the corrugations extending essentially radially from the central portion up to the side wall. The width Lx of the support rays can vary depending on the distance r from the center of the capsule in order to take into account the width of the flow channels 26 for supporting the filter so as to prevent its collapse at any point on its surface.

The radially inner end 30 of the support rays 25 surrounds a low chamber 32 allowing the lower wall portion 25 of the bottom wall to be perforated and the perforating device to penetrate into the capsule, as illustrated in FIGS. 2 a and 2 b. The upper surface 29 of the support rays 28 can be essentially flat, have a slight convex bulge, as illustrated, or can have a non-flat surface such as a corrugated one, or having protuberances to form small islets or support points for the filter membrane while still leaving spaces between the protuberances for the passage of liquid through the filter and into the flow channels 26. The aim is to have a filter membrane surface that is well supported by the bottom of the capsule, which still having an unencumbered and free surface for passage of the liquid through the filter membrane.

The filter membrane 22 can be glued or fastened to the bottom wall only at its circular periphery, but the filter membrane can also be glued or welded at several points or along radial lines where it is in contact with the upper surface 29 of the support rays.

The maximum insertion depth H1 of the perforating member 10 of the perforating device in the capsule relative to the lower wall portion 30 is preferably between 0.7 and 0.9 times the depth H3 of the central portion. The ratio H3/D3 of the depth H3 of the central portion relative to the diameter D3 of the central portion is advantageously between 1/3 and 2/3, preferably between 2/5 and 3/5. The ratio D3/D4 of the diameter D3 of the central portion 24 relative to the diameter D4 of the peripheral portion 23 lies preferably between 1/3 and 1/5, advantageously between 3/10 and 3/12, so as to have a large peripheral filtration area and a very unencumbered central outflow opening. The angle of inclination α of the outflow channels relative to the plane of the filter membrane 22 lies preferably between 10° and 30°, advantageously between 13° and 23°, in order to have a slope ensuring good outflow of the liquid passing through the filter while still having a capsule with a stable and compact shape.

The perforating device 6 includes a perforating member 10 for opening the bottom of the capsule. In the illustrated embodiment, the perforating member 10 advantageously includes a blade having a circular, or essentially circular, shape, with perforating points for cutting an essentially circular opening in the lower wall portion 25 of the bottom wall 16. The perforating points in the illustrated embodiment have the shape of saw teeth. The perforating member 10 is mounted on the free end of a tubular support 17 forming a central outflow passage 19. When a drink is prepared, water is injected through the upper wall by a perforating injecting head (not shown) into the internal volume. The bottom wall of the capsule can be perforated at three different times depending on the type of drink to be prepared and the operating parameters of the machine: before water is injected, at the same time as water is injected or advantageously after water injection has started to ensure a definite wetting time for the substance in the capsule before the drink is allowed to flow out of the capsule.

When the lower wall portion is perforated, the tubular support 17 and the blade 10 penetrate into the low chamber 32. The tubular support 17 is equipped with a plurality of side openings 14 allowing the drink flowing through the filter to flow along the channels 26 and to leave the capsule through the side openings 14 located at the level of the low point of the low chamber and to then drop into the central passage 19 at an outflow opening of the machine (not shown).

The circular blade 10 can, in one embodiment, advantageously include an interruption 11 so that the blade does not cover the full circle, so that the sectioned portion of the lower wall portion does not detach completely from the rest of the bottom wall.

The perforating device 6 can also advantageously include a plunger 12 positioned in the central passage 19. The plunger can serve to prevent the sectioned lower wall portion from sinking into the central passage or can serve to constitute a support for the central portion of the filter membrane 22 after perforation or sectioning of the bottom wall. In a first variant, the plunger is mounted in a fixed manner inside the central passage 19. In a second variant, the plunger is movable axially in the direction A perpendicular to the filter membrane and driven by a piston arm or rod (not shown). In this second variant, after perforation of the lower wall portion 30, the plunger is raised to extend past the blade and bear on the filter membrane 22. Thus, the filter membrane 22 is supported in its central portion against the pressure of the liquid and of the substance in the internal volume of the capsule during the extraction of the drink. The movable plunger also prevents the filter membrane 22 from pressing against the perforating member 10, which could unintentionally perforate the filter membrane.

In the illustrated embodiment, the plunger includes a peripheral ring 15 supporting a grille 13 for passage of a liquid through the plunger. The plunger can, however, include other forms of grille or configurations extending over part or all of the passage section 19 and having orifices or openings to allow the liquid to pass. Advantageously, this variant makes it possible to have excellent support for the filter membrane and allow the use of a very thin filter membrane, and hence low resistance to the flow of the liquid.

The corrugated shape of the peripheral portion 23 of the bottom wall makes it possible to have a capsule with very small thickness of the bottom wall and also of the side wall, while still providing sufficient rigidity for the shell to be self-supporting and capable of withstanding the extraction pressure. Also, the rigidity of the peripheral portion 23 makes it possible to have a lower wall portion 30 that is very thin and able to be easily perforated or sectioned.

The base 8 of the perforating part can advantageously include a corrugated surface with rays 5 and troughs 7 conforming to the shape of the bottom wall of the capsule for good seating and positioning of the capsule in the machine. The corrugated base also makes it possible to reinforce the stability of the bottom wall of the capsule during perforation of the lower wall portion and to then support the capsule despite a certain softening of the plastic material at the extraction temperature which reaches 100° C.

LIST OF REFERENCES IN THE FIGURES

-   -   2 capsule     -   3 internal volume     -   16 bottom wall     -   24 central portion     -   23 peripheral portion     -   28 supporting rays     -   30 radially inward end     -   29 upper surface     -   26 flow channels     -   18 side wall     -   upper (membrane) wall     -   21 rim     -   20 upper surface     -   22 filter membrane     -   32 low chamber     -   4 perforating part of the device     -   6 perforating device     -   12 plunger     -   13 grille     -   15 ring     -   17 tubular support     -   14 outflow opening     -   19 central outflow channel     -   10 perforating member     -   blade with saw teeth     -   11 interruption     -   8 base     -   9 opening     -   7 troughs     -   9 rays 

1-15. (canceled)
 16. A capsule for preparing a beverage by injecting water into the capsule, the capsule including a side wall and a bottom wall forming a self-supporting shell, an upper wall enclosing a sealed volume within the shell containing a substance to be extracted, and a filter membrane inside the sealed volume positioned on a bottom wall, wherein the bottom wall includes a peripheral portion and a central portion extending below the filter membrane at a non-zero depth and including a lower wall portion configured so as to be perforated or sectioned by a perforating device of a machine for preparing a drink by injecting water into the capsule in order to create one or more escape passages for the flow of the beverage passing through the filter membrane, the peripheral portion including flow channels extending radially from the lower wall portion toward the side wall, interposed between the support rays extending to the level of the filter membrane and forming supports for the filter membrane against the pressure of the water injected into the capsule and pressing on the substance contained in the capsule.
 17. The capsule according to claim 16, wherein the support rays and the flow channels form a corrugated surface, the generating lines of the corrugations extending essentially radially from the central portion to the side wall.
 18. The capsule according to claim 16, wherein a ratio between a diameter (D3) of the central portion relative to a diameter (D4) of the peripheral portion lies between 3/10 and 3/12.
 19. The capsule according to claim 16, wherein the angle of inclination (a) of the flow channels relative to the filter membrane lies between 13° and 23°.
 20. The capsule according to claim 16, wherein a ratio H3/D3 of a depth H3 of the central portion relative to a diameter D3 of the central portion is between 2/5 and 3/5.
 21. The capsule according to claim 16, wherein radially inward ends of the support rays surround a low chamber allowing the lower wall portion to be perforated and the perforating device to penetrate into the capsule.
 22. The capsule according to claim 16 associated with a perforating device, wherein the perforating device includes a perforating member for opening the bottom of the capsule, the perforating member including a blade having a circular, or essentially circular, shape configured to section an opening in the lower wall portion of the bottom wall.
 23. The capsule associated with a perforating device according to claim 22, wherein the blade includes perforation points in the form of saw teeth.
 24. The capsule associated with a perforating device according to claim 22, wherein the perforating member is mounted on the free end of a tubular support forming a central flow passage.
 25. The capsule associated with a perforating device according to claim 22, wherein the blade includes an interruption so that the blade does not cover the full circle, configured so that the lower wall portion that is sectioned is not completely detached from the rest of the bottom wall.
 26. The capsule associated with a perforating device according to claim 22, wherein the perforating device includes a plunger positioned in the central passage.
 27. The capsule associated with a perforating device according to claim 26, wherein the plunger is movable axially in the direction A perpendicular to the filter membrane configured to bear on the filter membrane after perforation of the bottom wall of the capsule.
 28. The capsule associated with a perforating device according to claim 26, wherein the plunger includes a grille for passage of the liquid through the plunger.
 29. The capsule associated with a perforating device according to claim 22, wherein the perforating device includes a base having a corrugated surface with rays and troughs configured for seating and positioning the bottom of the capsule.
 30. The capsule associated with a perforating device according to claim 22, wherein the maximum insertion depth (H1) into the capsule of a perforating member of the perforating device relative to the lower wall portion is between 0.7 and 0.9 times the depth (H3) of the central portion. 